Next Article in Journal
The Relationship between Unbilled Accounts Receivable and Financial Performance of Construction Contractors
Next Article in Special Issue
Sustainability Performance of National Bio-Economies
Previous Article in Journal
Agricultural Internet Entrepreneurs’ Social Network Behaviors and Entrepreneurship Financing Performance
Previous Article in Special Issue
Biomass-Based Innovations in Demand Driven Research and Development Projects in Africa
Open AccessArticle

Biogas Potential of Coffee Processing Waste in Ethiopia

1
Institute of Agricultural Engineering, Tropics and Subtropics Group(440e), University of Hohenheim, 70599 Stuttgart, Germany
2
State Institute of Agricultural Engineering and Bioenergy, University of Hohenheim, 70599 Stuttgart, Germany
*
Author to whom correspondence should be addressed.
Sustainability 2018, 10(8), 2678; https://doi.org/10.3390/su10082678
Received: 27 June 2018 / Revised: 26 July 2018 / Accepted: 28 July 2018 / Published: 31 July 2018
Primary coffee processing is performed following the dry method or wet method. The dry method generates husk as a by-product, while the wet method generates pulp, parchment, mucilage, and waste water. In this study, characterization, as well as the potential of husk, pulp, parchment, and mucilage for methane production were examined in biochemical methane potential assays performed at 37 °C. Pulp, husk, and mucilage had similar cellulose contents (32%). The lignin contents in pulp and husk were 15.5% and 17.5%, respectively. Mucilage had the lowest hemicellulose (0.8%) and lignin (5%) contents. The parchment showed substantially higher lignin (32%) and neutral detergent fiber (96%) contents. The mean specific methane yields from husk, pulp, parchment, and mucilage were 159.4 ± 1.8, 244.7 ± 6.4, 31.1 ± 2.0, and 294.5 ± 9.6 L kg−1 VS, respectively. The anaerobic performance of parchment was very low, and therefore was found not to be suitable for anaerobic fermentation. It was estimated that, in Ethiopia, anaerobic digestion of husk, pulp, and mucilage could generate as much as 68 × 106 m3 methane per year, which could be converted to 238,000 MWh of electricity and 273,000 MWh of thermal energy in combined heat and power units. Coffee processing facilities can utilize both electricity and thermal energy for their own productive purposes. View Full-Text
Keywords: husk; pulp; parchment; mucilage; methane; renewable energy husk; pulp; parchment; mucilage; methane; renewable energy
Show Figures

Figure 1

MDPI and ACS Style

Chala, B.; Oechsner, H.; Latif, S.; Müller, J. Biogas Potential of Coffee Processing Waste in Ethiopia. Sustainability 2018, 10, 2678.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop